Three-dimensional blast-wave-driven Rayleigh–Taylor instability and the effects of long-wavelength modes

Abstract

This paper describes experiments exploring the three-dimensional (3D) Rayleigh–Taylor instability at a blast-wave-driven interface. This experiment is well scaled to the He/H interface during the explosion phase of SN1987A. In the experiments, ∼5 kJ of energy from the Omega laser was used to create a planar blast wave in a plastic disk, which is accelerated into a lower-density foam. These circumstances induce the Richtmyer–Meshkov instability and, after the shock passes the interface, the system quickly becomes dominated by the Rayleigh–Taylor instability. The plastic disk has an intentional pattern machined at the plastic/foam interface. This perturbation is 3D with a basic structure of two orthogonal sine waves with a wavelength of 71 μm and an amplitude of 2.5 μm. Additional long-wavelength modes with a wavelength of either 212 or 424 μm are added onto the single-mode pattern. The addition of the long-wavelength modes was motivated by the results of previous experiments where material penetrated unexpectedly to the shock front, perhaps due to an unintended structure. The current experiments and simulations were performed to explore the effects of this unintended structure; however, we were unable to reproduce the previous results.

Simulation of fabrication variations in supernova hydrodynamics experiments

“…Once the image is calibrated relative to this grid, the same features used in this paper are found for analysis e that is, the bubble tip, spike tip, and shock position. It has been shown that there is a relative error of AE10 mm in the calculation of the position of these features [7]. Due to this relative error, the only variations that would be able to be definitively seen on an actual experimental image according to Table 3 would be a 3.162 mm and a 10 mm glue layer.…”

“…Characterization of the polyimide disk for a sample target revealed that the CHBr strip was depressed roughly w5 mm below its proper position, causing a vacuum gap at the interface between the drive disk and the CRF foam. It was hypothesized that such a depression may have been a source of this unexpected morphology, but simulation results in which such a depression was modeled exhibited little to no increase in spike penetration [7].…”

“…To obtain these results, we modified an existing simulation model [7,8] to include variably-sized glue layer surrounding the CHBr strip. A convergence study using this model is presented below.…”

Potential SiO2/CRF bilayer perturbation aerogel target for ICF hydrodynamic instability experiment

“…Due to the controllable density and nano-scale homogeneous microstructure, aerogels are widely used in fabricating ICF targets, such as silica aerogel shell [14,15], porous carbon sphere [16] and shock wave tube [17,18]. In this article, we designed and fabricated SiO 2 /CRF bilayer aerogel target with perturbation patterns in the interface.…”

Experiments in ICF, materials science, and astrophysics

“…3d. These scaled SN experiments have been moved to the Omega laser over the past 10 years and generated a wealth of scaled dynamics to compare SN simulation codes against [39][40][41][42][43]. A variety of interesting additional novel HED laboratory astrophysics applications, as well as SNe, are described in several review articles [44][45][46].…”